Introduction: Excessive flexion at the distal interphalangeal (DIP) joint disrupts the extensor mechanism and leads to mallet finger injuries. The goal of management is to restore active DIP joint extension, commonly achieved conservatively by extension splinting. There remains insufficient evidence to determine when surgical intervention is indicated. In children, factors such as an open epiphyseal plate and possible nonadherence to splinting regimens are considered. Currently, there are only three clinical studies evaluating pediatric mallet finger treatment in the English-speaking literature, and none report on conservative treatments. Children could benefit from the conservative treatment with a lower rate of serious complications and lower healthcare costs.

Materials & Methods: A retrospective review was performed on 94 patients who presented with 99 mallet finger injuries between 2013 and 2017 at a large pediatric hospital. Patient characteristics, treatments, outcomes, and radiographic data were collected. Unpaired t-tests with Welch's correction and chi-square goodness of fit tests were used to determine differences in DIP joint extension lag and rate of functionally significant complications from treatment between injuries of acute vs delayed (> 28 days) presentation as well as adherent vs nonadherent patients.

Results: The mean age of our study population was 13.7 (SD 2.4) years with 66 males (70%) and 28 females (30%). Most injuries occurred during recreation (78%). Most were treated non-operatively (99%). Only 1 patient was treated surgically. Various extension splints were employed for immobilization, with the most common being Stax (29%) and modified Alumafoam (27%) splints. The majority of injuries were bony mallets (80%), but isolated soft tissue injuries (20%) were also treated. Overall, patients had good outcomes with a mean DIP joint extensor lag of 1.7 (SD 5.6) degrees. There was no difference in extensor lag or complications between patients who presented in acute or delayed fashion. Treatment adherence was a strong predictor of clinical outcomes, with nonadherent patients more likely to experience residual extensor lag (p < 0.001) and significant complications (p = 0.001).

Conclusion: The majority of pediatric mallet finger injuries can be successfully treated conservatively with extension splinting. Absolute indications for surgery in this pediatric population remain unclear. Time to treatment had no difference in either residual DIP joint extensor lag or complications. Nonadherence to immobilization was a strong predictor of having residual extensor lag as well as significant complications. Therefore, we recommend conservative treatment for most cases of pediatric mallet finger, with a strong emphasis on treatment adherence.